Dear EarthTalk: What the heck is a “bionic leaf” and how does it help the planet?
-- William Friend, Billings, MT
Brainchild of Harvard biochemist Daniel Nocera, the “bionic leaf” is a small man-made solar collector that takes sunlight and water and turns it into any of a variety of usable fuels or fertilizers. Nocera’s first iteration, the so-called “artificial leaf,” was developed in 2011 at the Massachusetts Institute of Technology (MIT) and could split water into oxygen and hydrogen when exposed to sunlight in a process similar to (and inspired by) Mother Nature’s photosynthesis.
Nocera soon thereafter moved his lab to Harvard and teamed up with Pamela Silver there to create the “bionic” version which takes the concept further. There they fed the resulting hydrogen to an on-board catalyst, resulting in the generation of immediately useable downstream liquid “fuels” such as fertilizer for farms, isobutanol to run generators and engines, and PHB, a precursor for bio-plastic.
The team’s first version of the “bionic” leaf was about as efficient as natural photosynthesis, that is about one percent of the solar energy flowing in came out as biomass dense enough to use as fuel. But their most recent version ups the ante considerably, clocking in at 10 times more efficient than Mother Nature’s fastest growing plants.
“If you think about it, photosynthesis is amazing,” Nocera tells the Harvard Gazette. “It takes sunlight, water and air—and then look at a tree. That’s exactly what we did, but we do it significantly better, because we turn all that energy into a fuel.”
When mass-produced, these tiny solar “carbon-negative” fuel factories could be inexpensive enough for everyday people to use to power their vehicles and run their lights and appliances. Farmers with a small on-site array of bionic leaves could create enough fertilizer for their own needs instead of buying container-loads of synthetic fertilizer produced at sprawling CO2-spewing factories and shipped for thousands of miles.
The widespread application of bionic leaves could be especially advantageous in developing countries (and remote areas in general) where access to conventional fuels and fertilizers is limited and expensive or non-existent. Nocera hopes his work can bring the poor of the world their “first 100 watts” of energy through one form or another of the technologies he is developing. A Harvard-funded pilot program putting bionic leaves to use in India is just getting off the ground and Nocera hopes to expand globally within the near future.
The vision is for retiring every fossil fuel out there and replacing them with solar fuels from your own “bionic” garden. Imagine a world with no more utility bills or lining up at the gas pump? “You can use just sunlight, air and water,” concludes Nocera, “and you can do it in your backyard.”
CONTACTS: Nocera Lab, nocera.harvard.edu; Silver Lab, silver.med.harvard.edu; Harvard Gazette, news.harvard.edu/gazette.
Dear EarthTalk: I suffer from occasional acne but am loathe to treat it with harsh chemicals. Do you know of all-natural ways to get rid of pimples or prevent them altogether? -- J. W., Miami, FL
Acne—when sebum from oil glands under the skin clogs pores causing small bacterial infections that lead to swelling and discomfort—isn’t just a temporary annoyance during our teenage years; it plagues many of us throughout our adult lives as well. Some 85 percent of Americans are prone to at least occasional break-outs or worse. But common over-the-counter treatments—most contain either benzoyl peroxide or salicylic acid—can irritate the skin, eyes and lungs and are also linked to more serious health problems. The U.S. Food & Drug Administration (FDA) warns that the use of these over-the-counter topicals “can cause rare but serious and potentially life-threatening allergic reactions or severe irritation.”
Most of the top-selling brands incorporate benzoyl peroxide or salicylic acid in their acne treatments, but the only way to know for sure what’s inside any given product is to consult its label. Even better, do some research online before you buy. The Environmental Working Group’s free online Skin Deep database lists ingredients—and more important, the health and environmental threats—of over 120,000 personal care products, including more than 2,000 different acne treatments now or recently available on store shelves.
As far as alternative treatments go, tea tree oil, distilled from the leaves of Australia’s Melaleuca plant, seems to be a favorite. Studies have shown it to be equally as effective as benzoyl peroxide in reducing both the number of acne lesions and their severity. Likewise, Witch Hazel has similarly positive effects for most who try it, although there hasn’t been any scientific research to back that up yet.
According to National Geographic, dabbing a pasty mixture of powdered nutmeg and honey onto a problem pimple and leaving it there for 20 minutes can help unclog pores. Another trick is to soak a chamomile tea bag in cold water, squeeze it out, then hold it onto a pimple for 30 seconds. Icing a new pimple can also help reduce swelling and discomfort and shorten its lifespan. And smearing a little milk of magnesia on your face at bedtime can help prevent break-outs to begin with.
Healthline’s Kayla McDonnell suggests dabbing zits with apple cider vinegar or witch hazel or applying a honey/cinnamon mask. Her other tips for pimple remediation include regular exfoliation, taking a zinc and/or fish oil supplement, eating a low glycemic load diet, cutting back on dairy, reducing stress and exercising regularly.
If your acne is more severe, it might be worth consulting a dermatologist who can recommend prescription-strength treatments that can work with your body chemistry to limit the production of sebum in the first place. But drying, irritation and/or other side effects can ensue from these doctor-prescribed treatments as well, so be sure to let your doctor know so he or she can adjust the dosage or treatment plan.
CONTACTS: Skin Deep, www.ewg.org/skindeep; FDA’s “Topical Acne Products Can Cause Dangerous Side Effects,” bit.ly/acne-risks; “13 Powerful Home Remedies for Acne,” www.healthline.com/nutrition/13-acne-remedies; “The efficacy of 5% topical tea tree oil gel in mild to moderate acne vulgaris: a randomized, double-blind placebo-controlled study,” www.ncbi.nlm.nih.gov/pubmed/17314442.
Dear EarthTalk: If we already know how to capture carbon dioxide (CO2) and turn it into fuel, why aren’t we doing more of it? -- M.N. Daly, Springfield, MA
With recent measurements detecting the highest levels of atmospheric CO2 in human history—and experts warning we have less than a dozen years to turn around our profligate emissions to avoid cataclysmic changes—the time is nigh to start ratcheting down our carbon footprints. One solution that seems obvious but has been slow to get out of the starting gate is scrubbing large amounts of CO2 from the air and recycling it as a feedstock to produce carbon-neutral fuels to power our machines.
We have known how to capture CO2 from the air at large scale since the 1950s, but it wasn’t until the late 1990s that environmentalists started looking to so-called “Direct Air Capture” (DAC) as one of a suite of tools at our disposal for dealing with the greenhouse effect. Since then, researchers have been scrambling to come up with the most efficient ways to capture CO2.
Massachusetts-based start-up Carbon Engineering formed in 2011 in an effort to produce and eventually commercialize DAC technology that can use captured CO2 to make fuel at costs competitive with producing conventional fossil fuels. After several years of research and development and implementation of its technologies at a pilot plant in British Columbia, the company has been able to get the costs of capturing CO2 down to ~$100/ton—six times less than previous models predicted was possible.
But it’s what happens next that has environmental advocates jazzed. Carbon Engineering’s solar-powered electrolyzer splits water into hydrogen and oxygen, and then combines the hydrogen with previously captured CO2 to make carbon-neutral gasoline, diesel or even jet fuel. Assuming a $100/ton cost for capturing atmospheric CO2, the company can produce these eco-friendly fuels for about $1/liter, which is only marginally more expensive than their fossil-fuel counterparts. The hope is that costs will come down to below fossil fuels as demand grows and facilities scale up. Also, as more states follow California’s lead in requiring increasingly significant portions of their fuel mixes to come from “low-carbon” sources, demand for these green alternative fuels will rise and prices will likely drop even more.
R&D like this isn’t limited to the U.S. Spain’s SUN-to-LIQUID project uses unique solar concentration technologies that combine sunlight with oxygen and atmospheric CO2 to get three times as much energy out of the sun’s rays as existing solar “reactors.” The resulting “synthesis fuel” combines hydrogen and carbon monoxide and could be used to power vehicles or any type of engine equipped to deal with it.
And a team of Swiss and Norwegian scientists wants to put such technologies to use on millions of solar-powered floating islands at sea that could suck CO2 out of the air and turn it into fuel without taking up any land or bothering human neighbors. Such a plan may seem far-fetched, but we need to be open to new idea if we are going to turn the tide on climate change before we reach the dreaded “point of no return.”
CONTACTS: “Atmospheric CO2 hits record high in May 2019,” earthsky.org/earth/atmospheric-co2-record-high-may-2019; “Renewable transportation fuels from water and carbon dioxide,” https://phys.org/news/2019-06-renewable-fuels-carbon-dioxide.html; “A Process for Capturing CO2 from the Atmosphere,“ www.cell.com/joule/fulltext/S2542-4351(18)30225-3; “11 million floating solar farms could eliminate carbon emissions from transport,” www.chemistryworld.com/news/11-million-floating-solar-farms-could-eliminate-carbon-emissions-from-transport-/3010580.article.
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